As businesses rely on applications such as electronic mail and database management for core business operations, computer networking becomes increasingly more important. The most popular protocols used in networking are Ethernet and Fast Ethernet. A computer network is any collection of independent computers that communicate with one another over a shared network medium. Local area networks, or LANs, are networks usually confined to a geographic area, such as a single building or a college campus. LANs can be small, linking as few as two computers, but often link hundreds of computers used by thousands of people. LANs can include shared devices such as printers. The development of standard networking protocols and media has resulted in worldwide proliferation of LANs throughout business and educational organizations.
Often the network components are located in multiple physical places. Wide Area Networks, or WANs, combine multiple LANs that may be geographically separate. This is accomplished by connecting the different LANs using services such as dedicated leased phone lines, dial-up phone lines (both synchronous and asynchronous), satellite links, and data packet carrier services. Wide area networking can be as simple as a modem and a remote-access server for employees to dial into, or it can be as complex as hundreds of branch offices globally linked using special routing protocols and filters to minimize the expense of sending data over vast distances.
The network components are connected together by a network medium, such as cabling or a wireless channel. Network components such as hubs, bridges, transceivers, and routers make the network function, and include high-speed central processing units and switching devices to manage the network traffic. As more users are added, more data is moved over the network, and more network components are needed to manage the increased traffic.
The network administrators need to know the performance of the network, the level of traffic at which portions of the network are operating, and if any problems exist with network components and media. Typically, the performance, activity level, and existing problems are indicated using light emitting diodes (LEDs) that are associated with the network components. For example, the rate at which the LEDs flash may indicate the level of network activity.
FIG. 1 is a diagram of a conventional local area network system. Practically all LAN systems comprise a number of workstation computers 26 that are connected together to form a LAN 20. Other devices, such as printers and scanners, may be included in the LAN 20. The LAN 20 includes dedicated computers acting as a file server 21. The file server 21 provides access to attached storage devices, such as disk drives 28, which may contain shared data files. These data files are retrieved or updated by the file server 21 in accordance with requests transmitted by workstation computers 26 via the switch 24. The LAN 20 also allows the workstation computers 26 to connect to one another, and to be part of a wide area network (WAN).
The LAN 20 is essentially a shared-data transmission medium. As such, the capacity of the medium is shared between the workstation computers 26 attached to it. To provide higher performance of the LAN 20, network components, illustrated as LAN switch 24, are used. In the arrangement illustrated in FIG. 1, the LAN 20 is split into several independent segments 22A and 22B, which are interconnected with a LAN switch 24. The LAN switch 24 is programmed with, or automatically discovers, data regarding the connection arrangement of workstation computers 26 and corresponding segments. Because of this data, LAN switch 24 routes traffic only to relevant segments of the LAN, thus eliminating unnecessary traffic on other segments of the LAN 20. For large LANs, a substantial number of segments can be created to be interconnected by multiple LAN switches.
FIG. 2 is a block diagram of a conventional network component such as switch 24 of FIG. 1, and includes functional elements of the network component related to determining and displaying a network activity level. The network component 30 includes a central processor (CPU) sub-system 31; a switch application specific integrated circuit (switch ASIC) device 32 that includes within its boundary control & status registers, and counters 33, switching functions 35, medium access control sub-layer 36, and physical control sub-layer 37; a serializer/deserializer (SERDES) device 34 that includes within its boundary physical media access sub-layer 39, and physical medium dependent sub-layer 41; CPU interface 42, and activity-level indicator device 40 (sometimes referred to as a light emitting diode or LED, which is a type of an activity level indicator). Physical device boundary 38 also includes physical control sub-layer 37 (which is also part of switch ASIC 32), physical media access sub-layer 39, and physical medium dependent sub-layer 41. Network component 30 illustrates part of a particular LAN switch configuration that employs a switch ASIC. However, other configurations of network components exist which employ different functional partitioning.
CPU sub-system 31 is part of the processor controlling the network component 30, and generally includes a processor, RAM, ROM, and application programs stored in a memory. The network component 30 illustrated includes both a switch ASIC 32 and SERDES device 34, with the physical layer 38 including portions of both. An activity-level indicator device 40 is provided for each port being monitored, and typically is coupled to and driven from CPU sub-system 31. A network component with one hundred ports would typically have one hundred activity-level indicators, one assigned to each port.
Control & status registers, and counters 33 retain information related to the activity counts of the network component, including the transmission activity count and the reception activity count for each port. A method of driving an activity-level indicator 40 is to have CPU sub-system 31 read the control & status registers and control information 33 approximately every millisecond. CPU sub-system 31 then generates the control signal that turns the activity-level indicator device 40 on and off many times per second. The control signal generated in this manner often reflects activity counts for a port, and the activity-level indicator driven by the signal may become saturated and stays on continuously even though the port is not operating at its maximum level.
Another conventional method for determining and displaying network activity levels includes employing the switch ASIC 32 to convert each incident of network activity into a control signal that turns the activity-level indicator device 40 on and off. This method provides a one-to-one correlation between network activity and flashes. Because an incident of network activity happens faster than the eye can see, the control signal generated by the switch ASIC 32 stretches the incident so the flash of the activity-level indicator device 40 can be seen. As network activity level increases above a relatively low level, the one-to-one correlation of activity to flashes saturates the activity-level indicator device 40 and it stays on continuously. This gives a false impression that the network is very busy, and fails to adequately communicate network activity above a relatively low level.
There are other problems, however, with the present way of indicating the network activity level. The LEDs for a network component could be driven by the CPU in the network component, and there is usually a separate LED for each port. Traffic levels are sampled and computed by software operating in the CPU of the network component. The LED display for each port is driven directly by the CPU writing to a register to turn the LED on and off. This causes a problem because, to provide the network administrators with the information they need, the LED software runs at a high rate and consumes a large amount of CPU resources that are better served performing more critical functions in the network component. Another problem exists because traffic levels may not be effectively depicted by simply blinking a LED. Because of the high-speed networks presently being used, simply blinking a LED at a rate proportional to the traffic count may not adequately depict the traffic level to the administrator. For example, once the activity reaches a certain level, the LED may blink so fast that it appears to be solidly on.
Another problem exists because a network component may serve more than one hundred networked devices, such as computer workstations. Each computer may be connected to the network component at an individual port, each port having an LED activity indicator on the network component. When traffic counts are similar for multiple ports, the present method often presents multiple LEDs blinking in unison when the ports and the network media are functioning normally. However, multiple LEDs blinking in unison can be a sign of a problem with the network, and may cause administrators unfounded concern.